Reviewing anything, from performance to interface changes, becomes much easier with a live environment and so Review Apps can make a large impact on your development flow.

What are Review Apps?

A Review App is a mapping of a branch with an environment. The following is an example of a merge request with an environment set dynamically.

In this example, you can see a branch was:

Successfully built.

Deployed under a dynamic environment that can be reached by clicking on the View app button.

How do Review Apps work?

The basis of Review Apps in GitLab is dynamic environments, which allow you to dynamically create a new environment for each branch.

Access to the Review App is made available as a link on the merge request relevant to the branch. Review Apps enable you to review all changes proposed by the merge request in live environment.

Use cases

Some supported use cases include the:

Simple case of deploying a simple static HTML website.

More complicated case of an application that uses a database. Deploying a branch on a temporary instance and booting up this instance with all required software and services automatically on the fly is not a trivial task. However, it is possible, especially if you use Docker or a configuration management tool like Chef, Puppet, Ansible, or Salt.

Review Apps usually make sense with web applications, but you can use them any way you'd like.

Implementing Review Apps

Implementing Review Apps depends on your:

Technology stack.

Deployment process.

Prerequisite Knowledge

To get a better understanding of Review Apps, review documentation on how environments and deployments work. Before you implement your own Review Apps: